[c-nsp] Load-sharing to 18 subinterfaces

[Kim Onnel]

Physical setup:

18 Customers links ---- DSLAM ---- PE ---- Core

On the PE router, we configured 18 subinterfaces for a customer,
load-sharing per-packet under the interfaces isnt working, because there is
a limitation on routing subnets on a number of interfaces, the simplest
solution is to put a diff. router for the customer, but what other solutions
are there other than multilink (CPU Killer) ?